1. Field of the Art
This invention relates to a hot-air circulation cooking oven for cooking food within a heating chamber by circulating hot air within the chamber using a fan.
2. Background of the Related Art
Generally, a hot-air circulation cooking oven has an inner casing defining a heating chamber for storing a cooking tray at its center and a pan-like cover attached to the rear plate of the inner casing to define a fan chamber in which a hot air circulation fan and heater are provided. A number of suction holes are cut, such as punched holes, in the center portion of the rear plate. A number of upper discharge holes and of lower discharge holes are cut in the upper and lower portions of the rear plate, above and below the suction holes. The upper and lower discharge holes are formed in a bandlike array extending in the horizontal direction. The fan is arranged opposite to the suction holes and driven by a motor which is provided external to the cover. A heater is ring-like in configuration and provided around the fan.
When the fan and heater are operated, with two cooking trays set within the heating chamber, air within the heating chamber is sucked into the fan chamber through the suction holes opening between the cooking trays, and is heated by the heater and becomes hot. The hot air is blown into the heating chamber through the discharge holes provided between the top plate of the inner casing and the upper cooking tray, and between the bottom plate of the inner casing and the lower cooking tray. The hot air flows toward the neighborhood of a door situated in front of the heating chamber, and then is sucked again through the suction holes into the fan chamber. In this away, the hot air is circulated within the heating chamber to cook the food set within the heating chamber.
In the cooking oven thus manufactured, the hot air has to be circulated up to the region remote from the discharge holes, i.e., around the door in front of the heating chamber. The portion of the cover facing the discharge holes is inclined toward the heating chamber. Thus the hot air from the fan is directed by the inclined portion toward the heating chamber and sent toward the neighborhood of the door far distant from the discharge holes.
In the aforementioned structure, the hot air can be circulated from the discharge holes into a zone far from the discharge holes. However, more hot air is blown over food items on the cooking tray situated on the door side than the food items on the same cooking tray situated on the discharge hole side. This causes the food items set one behind another on the same tray to unevenly brown within the heating chamber.
Since the suction holes and discharge holes are provided adjacent to one another in the cooking oven, part of the hot air, which is discharged from the discharge holes, is short-circuited, thus causing it to blow from the suction holes directly into the fan chamber without being circulated through the heating chamber. As a result, this air cannot be effectively used to heat the food items and the heat is not adequately applied to the zone distant from the discharge holes, resulting in the uneven heating of the food items.
Because of this construction, it has been difficult in the conventional cooking oven to uniformly discharge hot air into the heating chamber to uniformly heat the food.